17. (1.09 x 102) x (2.79 x 10')
18. (5.75 x 104) / (4.71 102)
19.(3.38 x 106) x (7.80 x 104)
20. (7.04 x 10) / (9.45 x 10-)

Answer:

The Magician who lives in sand is called sand witch.

And sandwich is The name of one kind of food.

Answer:

Sandwich its food you eat it

Explanation:

Answer:

Oxygen is the nearest noble gas

Answer:

44.8 L

Explanation:

Using the ideal gas law equation:

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

At Standard temperature and pressure (STP);

P = 1 atm

T = 273K

Hence, when n = 2moles, the volume of the gas is:

Using PV = nRT

1 × V = 2 × 0.0821 × 273

V = 44.83

V = 44.8 L

Answer:

44.8L

Explanation:

Answer:

boron sulfide

b=boron

s=sulfer

Explanation:

Answer:

1.586x10^-9

Explanation:

To make a multiplication in scientific notation we need to multiply the coefficients and sum the exponents:

Coefficients: 2.600 * 6.1000 = 15.86

Exponents: -5 + (-5) = -10

The result is:

15.86x10^-10

As the scientific notation must be given with only 1 number in the left of the point:

Answer:

333g/L

Explanation:

The moles of CaCl2 in 6mEq are:

6mEq * (1mmol / 2mEq) = 3mmol CaCl2.

2Eq / mol because the charge of Ca is 2+

The mass is:

3mmol CaCl2 * (111mg/mmol) = 333mg = 0.333g

Molar mass: 2*35.5g/mol + 40g/mol = 111g/mol = 111mg/mmol

The liters are:

1mL * (1L / 1000mL) = 1x10⁻³L

The concentration in grams per liter is:

0.333g / 1x10⁻³L = 333g/L

Answer:

b

Explanation:

The chemical formula for a compound between Rb and the nitrate ion NO₃-1 is Rb(NO₃)₂. Hence, option B is correct.

Chemical formulas can be written for elements, compounds, and molecules. A compound is a substance made up of two or more different elements in a fixed ratio, and its formula shows the types of atoms and the number of each atom in the compound.

Rb(NO₃)₂ is the chemical formula for rubidium nitrate. It is an ionic compound composed of one rubidium cation (Rb+) and two nitrate anions (NO₃-) held together by ionic bonds.

The Rb+ ion has a charge of +1 and the NO₃- ion has a charge of -1, so two nitrate ions are needed to balance the charge of one rubidium ion. The overall charge of the compound is neutral.

Thus, option B is correct.

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Carbon has an atomic number of 6 so its electron configuration will be 1s² 2s² 2p². It has two orbitals as indicated with the 2 as its period number with the outer orbital have 4 valence electrons. So carbon is in the p-orbital, period 2 and in group 4.

Answer:

A FUSE is a type of conductor which protects the circuit by shorting it down when there is excess flow of current passing through it.

Explanation:

A fuse wire is made up of conducting materials such as alloy of tin and lead that has high resistivity. It has a low melting point of 200°C. It works based on the principle of heating effect of electric current. The functions of fuses include the following:

--> Fuses are made up of thin wire CONDUCTORS which interrupts or breaks the current flow of a circuit when in excess, thereby protecting the circuit from damage.

--> it prevents overload of current. In the event where too many appliances are connected to a single circuit, this can lead to overload which triggers a fuse to terminate the circuit connection.

--> It prevents total black-out: SWITCH-LIKE devices known as CIRCUIT BREAKERS share this function with the fuses. The nearest circuit breaks if any dysfunction occurs in the components of the circuit thereby preventing blackout.

Answer: The theoretical yield of alum is 12.09 g

Explanation:

Molarity is calculated by using the equation:

[tex]\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}[/tex] ......(1)

We are given:  

Molarity of sulfuric acid = 9.9 M

Volume of solution = 8.3 mL = 0.0083 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

[tex]\text{Moles of sulfuric acid}=(9.9mol/L\times 0.0083L)=0.08217mol[/tex]

The given chemical equation follows:

[tex]2Al+2KOH+4H_2SO_4+22H_2O\rightarrow 3H_2+2KAl(SO_4)_2.12H_2O[/tex]

By the stoichiometry of the reaction:

4 moles of sulfuric acid produces 2 moles of alum

So, 0.08217 moles of sulfuric acid will produce = [tex]\frac{2}{4}\times 0.08217=0.0411mol[/tex] of alum

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(2)

Molar mass of alum = 294.24 g/mol

Plugging values in equation 2:

[tex]\text{Mass of alum}=(0.0411mol\times 294.24g/mol)=12.09g[/tex]

Hence, the theoretical yield of alum is 12.09 g

Answer:

The correct answer is - may not be typical, and participant burden.

Explanation:

The 24-hour recall is nothing but a retrospective method of diet assessment. In this method, an individual is interviewed about his or her diet consumption during the last 24 hours.

The disadvantages or limitations of this method include the inability of a single day's intake to describe the typical diet, multiple recalls to intake, cost and administration time; participant burden, have to recall to reliably estimate usual intake.

Answer: protein bar,it gives alot of energy and wont upset your stomach!!

Answer: 287.46 billion km

Explanation: calculated it myself. nah but thats the answer

So, the molar mass of tetraethyl lead is

[tex]207.2+8(12.011)+20(1.00794)=\boxed{323.4468 \text{ g/mol}}[/tex]

Answer:

The correct answer is - Statement I is true, Statement-II is false.

Explanation:

Answer:

bronze, copper

Explanation:

bronze is used to make medals and carve statues

copper is used to make wire and utensils

Answer:

See explanation

Explanation:

9g of water contains : 9g/18 g/mol = 0.5 mole of water

1) 2 moles of hydrogen yields 2 moles of water

x moles of hydrogen yields 0.5 moles of water

x= 2 × 0.5/2 = 0.5 moles of hydrogen

Mass of hydrogen = 0.5 moles × 2 = 1 g of hydrogen

2) Number of moles of Al(OH)3 = 468 g/ 78 g/mol = 6 moles

2 moles of Al(OH)3 yields 3 moles of H2O

6 moles of Al(OH)3 yields 6 × 3/2 = 9 moles of H20

Mass of water =9 moles × 18 g/mol = 162 g of water

3) There are 13 oxygen atoms in the compound.

Mass of each oxygen atom = 16 g

Total mass of oxygen atoms = 13 × 16 = 208 g

Answer:

parietal pleura

Explanation:

The pleurae, which are serous membranes, divide the thoracic cavity's wall from the lungs. The parietal pleura covers the interior of the thorax, mediastinum, and diaphragm, while the visceral pleura covers the surface of the lungs.

The perianal pleura, the outer layer, is attached to the chest wall. The lungs, mediastinum's neurovascular structures, and bronchi are all covered by the inner layer (visceral pleura).

The pleura's role in breathing is to enable the lungs to expand and collapse as efficiently as possible.

The parietal and visceral pleura can move over one another without rubbing against one another thanks to the pleural fluid's lubricating properties. The pleural layers themselves produce this fluid.

Therefore, parietal pleura, which surround the lungs in thoracic cavity.

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Answer:

Generally SN1 reactions are carried out in polar protic solvents. The energy required for breaking the C-X bond is obtained through solvation of halide ion with the proton of the solvent. Tertiary alkyl halides undergo SN1 reaction very fast because of the high stability of tertiary carbocations.

Answer:

Barium Hydroxide

Explanation:

..........................

Answer:

Hey there

Explanation:

The process where organisms better adapted to their environment tend to survive and produce more offspring is called natural selection. It is one of the points of Darwinism by Charles Darwin.

Hope it helps

Answer:

B

Explanation:

A chemical reaction equation is balanced if the number of atoms of each element on the right hand side of the reaction equation is the same as the number of atoms of the same element on the left hand side of the reaction equation.

By inspection, the chemical reaction written in the question is a balanced chemical reaction equation.

However, the statement in option B that more molecules of N2 are needed to produce NH3 than molecules of H2 is a false statement since only one mole of N2 and three moles of H2 are required to produce NH3 according to the reaction equation as written in the question.

The equation Fe + CuSO₄ → Cu + FeSO₄ illustrates the single displacement reaction. Hence Option (D) is the correct answer.

A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound.

The starting materials are always pure elements, such as a pure zinc metal, iron or hydrogen gas, plus an aqueous compound.

Therefore, the equation Fe + CuSO₄ → Cu + FeSO₄ illustrates the single displacement reaction. Hence Option (D) is the correct answer.

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Answer:

Thompson's experiments with cathode ray tube showed that every atom contains a small amount of negatively charged subatomic particles. Thomson proposed the plum pudding model of the atom.

Explanation:

Answer:

As you turn the tube you can see patterns of colors at the other end of the tube. A kaleidoscope works by reflecting light. Light travels in a straight line. When light bumps into something it changes direction.

Kaleidoscopes are made with two or more mirrors. Light reflecting between these mirrors produces multiple virtual images of stunning beauty. ... Light rays are assumed to bounce off the mirrors like a ball bounces off a hard surface. Formally stated, the angle of incidence equals the angle of reflection.

Explanation:

Answer:

A) Q + XZ = X + QZ is a single displacement reaction.

B) Q + Z = QZ is a synthesis reaction

C) QT = Q + T is a decomposition reaction

D) QT + XZ = QZ + XT is double replacement reaction.

Explanation:

A) Q + XZ = X + QZ

This is a single displacement reaction because it is one in which one element is substituted for another one in a compound. In this case X is substituted for Q.

B) Q + Z = QZ

This is a synthesis reaction because Q and z combine to form a single product QZ.

C) QT = Q + T

This is a decomposition reaction because the compound QT breaks down to form 2 simpler substances Q and T.

D) QT + XZ = QZ + XT

Thus is a double replacement reaction because QT and XZ have exchanged cations to form new compounds QZ and XT

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Explanation:

I hope this helps

Answer:

a decrease in concentration affects the equilibrium

Explanation:

disturbance: equilibrium was disturbed by a decrease in concentration

response:system acts so as to increase concentration

reaction favoured: forward reaction

concentration: concentration of ...... ND ....... increases ND that of ......(product)decreases